1. Field of the Invention
The present invention relates to food processing apparatus and, more particularly, to juicer apparatus having a spiral rotary blade and a pressing portion and adapted to cut and squeeze material, such as fruits and vegetables to extract juice and residual matter from the latter material.
2. Description of the Prior Art
A typical known type of juicer apparatus has a disc-shaped rotary blade adapted to be rotated at a high speed and a centrifugal separating cage surrounding the rotary blade and adapted to rotate unitarily with the latter. The material to be processed is pressed by a pushing rod against the rotary blade which is rotating at a high speed together with the centrifugal separating cage, so that the liquid content or juice of the material is expelled by centrifugal force through small holes in the centrifugal separating cage, while the residual solid content of the material is moved and discharged upward along the inner peripheral surface of the centrifugal separating cage.
In this known type of juicer, it is necessary to rotate the blade and the cage at a high speed of 10,000 r.p.m. or higher, in order to obtain a centrifugal force large enough to extract the juice. In addition, the centrifugal separating cage has a very large diameter and produces loud noise during rotation. In addition, the rotary members have to be fabricated to exhibit a good balance of mass. The rotary blade rotating at a high speed produces a loud noise when it cuts and crushes the material, so that the level of noise generated by the juicer as a whole is impractically high.
In addition, the solid residual matter tends to attach to the inner peripheral surface of the centrifugal separating cage. The balance of the rotary body often fails due to uneven attaching of the residual matter to further increase vibration of the apparatus. Furthermore, air is trapped by the juice from the crushed material as the juice flows through the small holes of the cage thus permitting the juice to contain air bubbles which cause an undesirably easy separation of pulp from the water. In addition, the vitamin constituents are liable to be broken down due to the contact with air, thus diminishing the nutritive power.
Another problem is that the residual solid matter attaches to the centrifugal separating cage, case, lid and other parts. Particularly, the fibrous content of the residual solid matter enters into the small holes in the centrifugal separating cage. Troublesome work is required to remove and wash away this residual solid matter after use.
Japanese Utility Model Application Publication Nos. 1990/1954 and 1193/1959 disclose different juicers having spiral rotary blades. In these known juicers, the spiral rotary blade presses and squeezes the material while transferring the same. The cutting and crushing of the material is largely owed to the mutual cutting effect of the material. Therefore, the material is often wasted before the juice is fully extracted, so that the nutritive value due to pulp contained by the juice is reduced.
Under these circumstances, the present inventors have proposed a juicer comprising a rotary member having a spiral inlet cutting portion for effecting cutting of the material and a spiral pressing portion connected to the cutting portion, a cylindrical squeezing case rotatably accomodating the rotary member and a filter attached to the lower side of the squeezing casing.
In operation, the material to be processed is, thrown into the juicer through an inlet, is cut and pressed by the rotary member and is shifted toward the outlet end while releasing the juice from a juice outlet, so that juice having a high nutritive value is produced.
In this juicer, however, it is not possible to provide the bearing of the rotary member at the end of the squeezing case, because the juice outlet and the residual matter outlet are formed at the end of the case. This inconveniently prevents the clearance between the outer end of the blade of the rotary member and the inner peripheral surface of the case from being reduced to a sufficiently small level, so that the material to be processed is crushed only coarsely, thereby resulting in a low efficiency of squeezing. In addition, it is necessary to place a receiver for receiving residual matter at the end of the squeezing case, so that the size of the juicer as a whole is increased impractically.